The answer is x equals -1
16 pi? well... 16 pi = 50.2654824574. So... the diameter would be 16 and the radius would be 8. I think!
Answer:

area: 136 cm
perimeter: 48 cm
Step-by-step explanation:
For the first one just subtract

for the second one you just have to break it into smaller, more digestible pieces (work below)
Complement of JEF is 50 degrees
supplement of JEF is 140 degrees
complement of DON is -34 degrees or depending on your teacher, the answer is NONE.
supplement of DON is 56 degrees